1. Field of the Invention
The present invention relates to a zoom lens barrel, and more particularly, to a zoom lens barrel having an advanceable and retractable lens frame.
2. Description of the Related Art
In recent years, digital cameras have showed tendencies to be enhanced in performance and to be more compact and slimmer. Accordingly, in order to be adapted to the tendencies, the zoom lens barrels incorporated in the cameras are in such a state as to be desired to have high magnifications and shorter barrel lengths in the lens optical axis directions in the collapsed state. As the above described zoom lens barrel, for example, the one having an advanceable and retractable barrel structure formed by a plurality of stages is generally applied.
The above described zoom lens barrel includes a fixed frame placed at an outermost periphery, a plurality of movable frames which are fitted in an inner portion of the fixed frame by being superimposed thereon toward an inner peripheral side, and are advanceable and retractable in an optical axis direction, and a plurality of lens holding frames (lens frames) supported by an inner peripheral portion of any of the above described plurality of movable frames. The above described plurality of movable frames are provided with cam means formed by cam grooves and cam followers for frame advancing and retracting drive. The above described plurality of advancing and retracting frames are sequentially drawn out at the time of zooming, and the above described holding frames supported by the advancing and retracting frames at the inner peripheral side performs advancing and retracting movement in the optical axis direction. As the zoom lens barrel having such a configuration, there is the one disclosed by Japanese Patent Application Laid-Open Publication No. 2005-173413, for example.